<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #div1 {
            /* width: 200px; */
            height: 100px;
            background: #f00;
        }
    </style>
</head>

<body>
    <div id="div1" style="width: 200px"></div>
    <script>
        // eval("function test(){alert('haha')} test()");

        // var fnStr = "";

        // if(false){
        //     fnStr = "function test(){alert('haha')}";
        // }else{
        //     fnStr = "function test(name){alert(name)}";
        // }

        // eval(fnStr);

        // test("lisi");

        // eval("while(true){alert('haha')}");

        // console.log(  isNaN("abc")  );

        // console.log(parseInt("0x1234"));

        var oDiv1 = document.getElementById('div1');
        oDiv1.style.width = (parseInt(oDiv1.style.width) + 50) + 'px';
        console.log(oDiv1.style.width);
    </script>
</body>

</html>